For the first time ever, a successful treatment has been found for the devastating brain disease, Huntington's. The inherited condition, which resembles a combination of dementia, Parkinson's and motor neurone disease, affects hundreds of thousands of people in the US and Europe. The scientists who developed the new gene therapy, and people who have the disease, say its a huge breakthrough that could give people a better quality of life for decades.

Also: we meet the teacher who's launched a Happiness Project to help her pupils learn about what really matters, and is encouraging others to do the same.

Presenter: Oliver Conway. Music composed by Iona Hampson